Embodiments of the present invention relates in general to semiconductor devices for use in integrated circuits (ICs). More specifically, embodiments of the present invention relates to improved fabrication methodologies and resulting structures for semiconductor device configurations (e.g., fin-type field effect transistors (FinFETs)) having strained and unstrained semiconductor device features formed on the same substrate.
Transistors are fundamental device elements of modern digital processors and memory devices. There are a variety of transistor types and designs that may be used for different applications, including, for example, bipolar junction transistors (BJT), junction field-effect transistors (JFET), and metal-oxide-semiconductor field-effect transistors (MOSFET). One type of transistor that has emerged within the MOSFET family of transistors, and which shows promise for scaling to ultra-high density and nanometer-scale channel lengths, is a so-called FinFET device. The channel of a FinFET is formed in a three-dimensional fin that may extend from a surface of a substrate, and the transistor's channel can be formed on three surfaces of the fin. Accordingly, FinFETs can exhibit a high current switching capability for a given surface area occupied on substrate.
The use of silicon germanium in semiconductor devices such as FinFETs provides desirable device characteristics, including the introduction of strain at the interface between the silicon germanium of the active device and the underlying semiconductor substrate. Accordingly, it is desirable to provide compressive strain in some features of a semiconductor device, including, for example, the fin of a fin-based semiconductor device such as a FinFET.